The present invention relates to novel dextranase-containing dentifrices which are enzymatically, physically and cosmetically stabilized in the presence of anionic surfactants by the addition of a dual anionic and amphoteric betaine surfactant system and a cationically modified hydrolyzed collagen protein stabilizer, to provide formula stability and retention of enzyme activity over time.
The prior art is replete with information relating to the effectiveness of dextranase against dental plaque, its dispersion and removal, as shown in an article by Bowen in the British Dental Journal, vol. 24 number 8, pp. 347-349, (Apr. 16, 1968); an article by Fitzgerald et al, in JADA, vol. 76, pp. 301-304, (February 1968); and an article by Duany et al, in Journal of Preventive Dentistry, vol. 2, No. 2, pp. 23-27, (March-April 1975). The dextranase enzymes also reduce the formation of dental caries and periodontal disease when applied topically. These enzymes degrade or break down the dextrans synthesized in the plaque from sucrose by strep. mutans. The dextrans serve as a glue for the cohesion of the plaque.
Accordingly, dextranase has been incorporated in conventional oral hygiene products such as toothpastes, rinses and chewing gum containing surface active cleansing and foaming agents, as shown in Japanese Patent Public Disclosure No. 56834/1973, and in British Patent No. 1,319,423 containing an anionic surfactant. These surfactants, especially anionic surfactants, tend to deactivate the enzymes such as dextranase, with rapid loss of enzyme activity in the absence of stabilization. Thus, it is difficult to make a stable and foaming dentifrice with dextranase. Accordingly, a number of stabilizers have been incorporated in dentifrice compositions containing dextranase. For example, U.S. Pat. No. 3,991,177 teaches the use of manganous and calcium ions to stabilize dextranases in the dentifrices in the presence of anionic surfactant such as sodium N-lauroyl sarcosinate. U.S. Pat. No. 3,981,989 discloses gelatin or peptone as the stabilizing agents for dextranases in the presence of sodium lauryl sulfate. U.S. Pat. No. 4,140,758 teaches the use of a metal ion selected from the group consisting of manganese, calcium, magnesium and mixtures thereof as a stabilizer/activator for dextranase. Japanese Patent No. 013318 by Lion, dated 2/6/1980, utilizes eugenol and 1-menthol as dextranase stabilizers in the presence of anionic surfactants. Japanese Patent No. 010350 by Lion Corp., dated 1/27/81, utilizes a mixture of dextranase and omega-amino acids in oral compositions to prevent bacterial plaque formation. French Patent Application No. 82/05799 discloses an oral composition comprising a mixture of dextranase and .alpha.-1,3 glucanase. U. K. Patent Application No. 2,061,727A utilizes aluminas and hydrated aluminas as the abrasive, in order to stabilize the dextranase in the dentifrice composition.
U.S. Pat. No. 3,562,385 discloses dental antiplaque and anticalculus compositions containing a mixture of a bis-biguanido compound, dextranase and sodium hexametaphosphate. U.S. Pat. No. 3,622,661 discloses oral preparations containing dextranase and the specific binder Irish moss or gum tragacanth to prevent separation upon standing. Oral antiplaque and/or anticalculus compositions containing dextranase are also disclosed in U.S. Pat. Nos. 3,630,924; 3,686,393; and 3,751,561. Oral compositions containing dextranase in combination with other enzymes are disclosed in U.S. Pat. No. 4,335,101. Dextranase has been modified by molecular alteration by the use of a phosphoprotein carrier and a reacting agent such as ethylchloroformate, in order to provide longer periods of activity in the oral cavity, as disclosed in U.S. Pat. No. 4,138,476.
Toothpastes having cosmetic and enzymatic stability containing a neutral protease of B. subtilis, stabilized by a partially hydrolyzed protein is disclosed in U.S. Pat. No. 4,058,596. The addition of a Group IIA metal ion to the neutral protease and hydrolyzed protein combination provides additional stability as disclosed in U.S. Pat. No. 4,058,595.
Although the problem of stabilizing dextranase in the presence of anionic surfactants is well known in the prior art, and has been solved by the addition of a variety of stabilizing agents as aforecited, there is no disclosure of the use of a dual surfactant system of anionic surfactants and amphoteric betaine and a cationically modified hydrolyzed collagen protein stabilizer, such as a quaternized hydrolyzed protein (Crotein Q).